The present invention relates to an electronic key registration system that registers an electronic key to a communication subject.
Japanese Laid-Open Patent Publication No. 2004-300803 discloses an electronic key system that performs encrypted communication to increase the confidentiality of an ID signal transmitted from an electronic key through a wireless connection. Since encrypted communication encrypts the ID signal transmitted from the electronic key through a wireless connection, it is difficult for a person who has acquired the ID signal in an unauthorized manner to obtain the ID of the electronic key.
The electronic key of such an electronic key system is registered in advance to a vehicle. The registration is performed by registering an ID, which is unique to the electronic key, in association with an encryption key to a controller installed in the vehicle. However, there is room for improvement in the level of security against unauthorized acquisition of the encryption key.